This invention relates to a water jet propulsion unit and more particularly to an improved arrangement for picking off a portion of the water pumped by the jet propulsion unit and using it for another purpose and separating foreign articles from the picked-off water and returning them to the jet propulsion unit.
Water jet propulsion units have a number of advantages over more conventional propeller type systems. For example, it is possible to operate the watercraft powered by the jet propulsion unit in much shallower water than with conventional propellers. In addition, a portion of the water which is circulated by the impeller of the jet propulsion unit can be used for a variety of other purposes. For example, this water may be delivered to the cooling jacket of the engine for circulation therethrough. Alternatively, the diverted water can be employed to operate a venturi type of pump for pumping water from the bilge of the watercraft.
In connection with these uses of the diverted water, there is, however, a problem. Because of the fact that the jet propulsion unit can be operated in shallow water, there is a likelihood that foreign particles may be pumped through the jet propulsion unit. This is true even if a strainer is utilized for the main portion of the jet propulsion unit. Such strainers are employed only to remove extremely coarse articles since smaller particles can present no basic problem to the operation of the jet propulsion unit.
If, however, these smaller particles are passed into the conduit that supplies the tapped off water, they can obstruct its flow. If the water is used for the cooling system of the engine, this will mean that the engine can be inadequately cooled. Alternatively, if the drawn off water is utilized for a venturi pump, then the venturi pump can itself become clogged.
It has been proposed to avoid these difficulties by providing a strainer in the drawn off water conduit. However, the strainer itself can become clogged and the same results will occur unless the strainer is serviced frequently.
It is, therefore, a principal object of this invention to provide an improved arrangement for separating foreign particles from the water drawn off of a jet propulsion unit.
It is a further object of this invention to provide a separator for such water wherein the removed particles will be returned and disposed of through the jet propulsion unit.
It is a further object of the invention to provide a separator for such water that will not require servicing.